Your Nose Microbiome Could Be Key to COVID-19 Susceptibility, Scientists Discover
In a revolutionary revelation that has the potential to transform our comprehension of how COVID-19 impacts individuals variably, researchers have pointed out an unexpected new factor in the fight against SARS-CoV-2: the bacteria residing in your nose.
A new study from scientists at George Washington University reveals that the nasal microbiome—the collection of microorganisms that occupy our nasal cavities—can considerably affect a person’s susceptibility to COVID-19 by modulating the levels of vital proteins utilized by the virus to invade human cells.
Essential Proteins and the Nose as COVID’s Entry Point
For a long time, it has been acknowledged that SARS-CoV-2 first penetrates the body through the respiratory system, with the nose serving as a crucial access point. However, a research team led by Associate Professor Cindy Liu at GW’s Milken Institute School of Public Health has discovered that the nose functions beyond being a mere passageway. Instead, its microbial inhabitants may actively influence the ease—or difficulty—with which the virus can enter.
Released in EBioMedicine on April 9, the study evaluated over 450 nasal swab samples from subjects, some of whom subsequently tested positive for COVID-19. Researchers targeted two proteins—ACE2 and TMPRSS2—known to be exploited by SARS-CoV-2 to attach to and merge with human cells. These proteins have been recognized as critical targets of the virus and are vital for the infection process.
The new results indicate that individuals exhibiting high expression of these proteins in their nasal cells were three times more likely to test positive for COVID. Even those with moderate protein levels faced double the risk compared to individuals with low expression. Alarmingly, the expression of these proteins frequently surged just days prior to a positive test, suggesting an increased window of vulnerability.
How Bacteria Affect Viral Entry
The most captivating aspect of the study lies in its analysis of what factors influence the variations in ACE2 and TMPRSS2 protein expression. The findings suggest that the nasal microbiome plays a crucial role.
“Certain bacteria in your nose might be preparing the environment—or even keeping the door ajar—for viruses such as SARS-CoV-2 to enter,” noted Daniel Park, senior research scientist and lead author of the study.
The research team identified three bacteria that were strongly linked to heightened protein expression—and consequently increased COVID-19 risk:
– Staphylococcus aureus
– Haemophilus influenzae
– Moraxella catarrhalis or M. nonliquefaciens
Approximately one in five participants harbored enough S. aureus to significantly raise their chances of elevated ACE2 and TMPRSS2 levels.
Conversely, the researchers discovered one bacterium, Dolosigranulum pigrum, that seems to provide a protective effect. Individuals with increased levels of this microbe exhibited lower expression of the viral entry proteins, indicating a possible defense against infection.
Differences in Infection Risk by Gender
Interestingly, the study also noted gender discrepancies in protein expression and infection risk. Women typically had higher baseline levels of the viral gateway proteins—a result in line with previous findings showing higher infection rates among women. However, when men did display elevated ACE2 and TMPRSS2 levels, their risk of virus contraction was even more pronounced.
This complexity implies that while gender exerts influence, the relationship between protein expression, hormone levels, immune reactions, and the microbiome might be more intricate than previously realized.
A New Direction for Prevention?
Beyond clarifying variations in infection rates, this study paves the way for innovative strategies to prevent respiratory viruses. Researchers are currently investigating whether strategies that modify the nasal microbiome—such as prebiotic nasal sprays or live bacterial therapies—could be utilized to diminish SARS-CoV-2 susceptibility.
“We are just starting to unravel the complex interaction between the nasal microbiome and our health,” Liu commented. “However, this research indicates that the internal ecosystem of our noses could be just as crucial as the masks we wear externally.”
The Future of Respiratory Wellness
As SARS-CoV-2 continues to adapt and remains a persistent threat, grasping individual biological risk factors is essential. This recent research indicates that it’s not solely about virus variants or vaccination status—but also about the microbial communities residing within each of us.
While traditional preventive measures such as vaccination, masking, and social distancing are still critical, future strategies for COVID-19 prevention might also incorporate monitoring the nasal microbiome and customizing treatments based on its makeup.
Indeed, something as seemingly trivial as the bacteria within your nose could be the next significant step in safeguarding public health against not only SARS-CoV-2—but other airborne pathogens that may arise.
As we steer through this evolving scenario, it’s becoming increasingly evident that the conflict against COVID-19 may be conducted on the most minuscule of home fronts—the microscopic confrontations occurring within our own nasal passages.